Improving Charge Injection for Organic Field‐Effect Transistor Array via Chemical Functionalized Van der Waals Top‐Contacts

Efficient charge injection at metal/semiconductor interface is of great importance for high-performance organic field-effect transistors (OFETs). In OFETs, top-contact configuration generally exhibits better injection efficiency but may induces thermal damage to organic layer and is intrinsically difficult to modified with chemisorbs at metal/semiconductor interface. Herein, a versatile, large-scale and damage-free metal integration strategy is reported to achieve efficient charge injection in OFETs by applying self-assembly monolayers (SAMs) functionalized van der Waals (vdW) top-contact electrodes. Centimeter scale metal electrodes are transferred onto organic single crystal to form OFETs array without residual left. vdW contact provides a clear and atomic sharp interface, and thus the inherent electronic structure and physical properties of the pristine heterostructure interface can be retained. Modifying fluorinated SAMs at metal/semiconductor interface alters the work function of Au by 350 meV, and thus reduces the energy barrier for charge injection. As a result, OFETs array exhibits excellent performance characteristics with an average mobility of 3.6 cm(2) V-1 s(-1), negligible hysteresis and a high on/off ratio above 10(6) on high-k AlOx dielectric. Organic unipolar inverters based on all vdW contact are also demonstrated. This strategy paves the way for both fundamental study and practical applications of organic electronics.